So my friend is sharing his server/libraries with me. Is there any way to share these shared libraries, with my “Guest” user or “Managed” user? So that I have two accounts that both see these shared libraries? Kind of a two accounts, one main and one (guest, managed), copied from the main one?
You cannot. Your friend can but not on ‘managed accounts’.
That is, a user that doesn’t have a regular plex.tv account.
What you can do is create a second plex.tv account and add that account to your Plex Home then share your libraries(give access to) to the newly created account, then ask your friend to give access to the their libraries aswell.
So you the admin will have your libraries & your friends shared libraries.
And your newly created managed plex.tv account will have access to your libraries & your friends.